 /*******************************************************************************
  * Copyright (c) 2000, 2005 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/

 package org.eclipse.ui.contexts;

 import java.util.SortedSet ;

 /**
  * <p>
  * A context manager tracks the sets of defined and enabled contexts within the
  * application. The manager sends notification events to listeners when these
  * sets change. It is also possible to retrieve any given context with its
  * identifier.
  * </p>
  * <p>
  * This interface is not intended to be extended or implemented by clients.
  * </p>
  *
  * @since 3.0
  * @deprecated Please use the "org.eclipse.core.commands" plug-in instead.
  * @see org.eclipse.core.commands.contexts.ContextManager
  */
 public interface IContextManager {

     /**
      * Registers an instance of <code>IContextManagerListener</code> to listen
      * for changes to properties of this instance.
      *
      * @param contextManagerListener
      * the instance to register. Must not be <code>null</code>. If
      * an attempt is made to register an instance which is already
      * registered with this instance, no operation is performed.
      */
     void addContextManagerListener(
             IContextManagerListener contextManagerListener);

     /**
      * Returns an instance of <code>IContext</code> given an identifier.
      *
      * @param contextId
      * an identifier. Must not be <code>null</code>
      * @return an instance of <code>IContext</code>.
      */
     IContext getContext(String contextId);

     /**
      * Returns the set of identifiers to defined contexts. The set is sorted by
      * the depth of the context within the tree of contexts. So, for example,
      * a child context will always appear before its parent.
      * <p>
      * Notification is sent to all registered listeners if this property
      * changes.
      * </p>
      *
      * @return the set of identifiers to defined contexts. This set may be
      * empty, but is guaranteed not to be <code>null</code>. If this
      * set is not empty, it is guaranteed to only contain instances of
      * <code>String</code>.
      */
     SortedSet getDefinedContextIds();

     /**
      * Returns the set of identifiers to enabled contexts. The set is sorted by
      * the depth of the context within the tree of contexts. So, for example,
      * a child context will always appear before its parent.
      * <p>
      * Notification is sent to all registered listeners if this property
      * changes.
      * </p>
      *
      * @return the set of identifiers to enabled contexts. This set may be
      * empty, but is guaranteed not to be <code>null</code>. If this
      * set is not empty, it is guaranteed to only contain instances of
      * <code>String</code>.
      */
     SortedSet getEnabledContextIds();

     /**
      * Unregisters an instance of <code>IContextManagerListener</code>
      * listening for changes to properties of this instance.
      *
      * @param contextManagerListener
      * the instance to unregister. Must not be <code>null</code>.
      * If an attempt is made to unregister an instance which is not
      * already registered with this instance, no operation is
      * performed.
      */
     void removeContextManagerListener(
             IContextManagerListener contextManagerListener);
 }

